CVE-2021-47434

MEDIUM
Published May 22, 2024 Modified Sep 25, 2025

Description

In the Linux kernel, the following vulnerability has been resolved: xhci: Fix command ring pointer corruption while aborting a command The command ring pointer is located at [6:63] bits of the command ring control register (CRCR). All the control bits like command stop, abort are located at [0:3] bits. While aborting a command, we read the CRCR and set the abort bit and write to the CRCR. The read will always give command ring pointer as all zeros. So we essentially write only the control bits. Since we split the 64 bit write into two 32 bit writes, there is a possibility of xHC command ring stopped before the upper dword (all zeros) is written. If that happens, xHC updates the upper dword of its internal command ring pointer with all zeros. Next time, when the command ring is restarted, we see xHC memory access failures. Fix this issue by only writing to the lower dword of CRCR where all control bits are located.

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CVSS v3.1 Score

5.5
MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected Products

Vendor Product
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel

References

Advisories & Patches

https://git.kernel.org/stable/c/01c2dcb67e71c351006dd17cbba86c26b7f61eaf https://git.kernel.org/stable/c/22bcb65ea41072ab5d03c0c6290e04e0df6d09a0 https://git.kernel.org/stable/c/62c182b5e763e5f4062e72678e72ce3e02dd4d1b https://git.kernel.org/stable/c/dec944bb7079b37968cf69c8a438f91f15c4cc61 https://git.kernel.org/stable/c/e54abefe703ab7c4e5983e889babd1447738ca42 https://git.kernel.org/stable/c/ff0e50d3564f33b7f4b35cadeabd951d66cfc570 https://git.kernel.org/stable/c/01c2dcb67e71c351006dd17cbba86c26b7f61eaf https://git.kernel.org/stable/c/22bcb65ea41072ab5d03c0c6290e04e0df6d09a0 https://git.kernel.org/stable/c/62c182b5e763e5f4062e72678e72ce3e02dd4d1b https://git.kernel.org/stable/c/dec944bb7079b37968cf69c8a438f91f15c4cc61 https://git.kernel.org/stable/c/e54abefe703ab7c4e5983e889babd1447738ca42 https://git.kernel.org/stable/c/ff0e50d3564f33b7f4b35cadeabd951d66cfc570

Frequently Asked Questions

What is CVE-2021-47434? +
In the Linux kernel, the following vulnerability has been resolved: xhci: Fix command ring pointer corruption while aborting a command The command ring pointer is located at [6:63] bits of the command ring control register (CRCR). All the control bits like command stop, abort are located at [0:3] bits. While aborting a command, we read the CRCR and set the abort bit and write to the CRCR. The read will always give command ring pointer as all zeros. So we essentially write only the control bits. Since we split the 64 bit write into two 32 bit writes, there is a possibility of xHC command ring stopped before the upper dword (all zeros) is written. If that happens, xHC updates the upper dword of its internal command ring pointer with all zeros. Next time, when the command ring is restarted, we see xHC memory access failures. Fix this issue by only writing to the lower dword of CRCR where all control bits are located. It has a CVSS v3.1 base score of 5.5 (MEDIUM).
How severe is CVE-2021-47434? +
CVE-2021-47434 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.
What products are affected by CVE-2021-47434? +
CVE-2021-47434 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2021-47434? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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